JPS61258388A - Magnetic bubble element - Google Patents

Abstract

PURPOSE:To improve bubble transfer characteristics by increasing the bit length of an element opposite to an outer corner compared with the bit length of other elements with a rectilinear transfer line and therefore increasing the distance between the tip of the outer corner and a cusp. CONSTITUTION:The diagram shows the form of a pattern near an outer corner of an ion implanting transfer line of a cell size (4mumX4mum). The length L of an element 7 opposite to an outer corner 4 of a rectilinear transfer line is larger than the length 4mum of other elements. In such a case, the lower limit margin is reduced and the margin width is increased as the length L increases more than 4mum in terms of the bias magnetic field margin for bubble transfer at the outer corner. When the length L is equal to 6mum, said margin is equal to the margin of the rectilinear transfer line. Thus the 13% margin width is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic bubble transfer path formed by ion implantation, and particularly to the shape of a straight transfer path near an outer corner having good bubble transfer characteristics.

[Background of the invention]

Elements that store binary information using cylindrical magnetic domains, that is, magnetic bubbles, present in a magnetic thin film such as magnetic garnet whose easy magnetization direction is perpendicular to the film surface are attracting attention. In particular, the ion implantation type magnetic bubble transfer path disclosed in U.S. Pat. No. 3,828,329 is suitable for increasing density, and is therefore being developed in various places.

The basic configuration of a magnetic bubble element is shown in Figure 1. This is of a type called a major/minor loop configuration, where the loop indicated by 1 is the minor loop, and the lines indicated by 2 and 2' are the major loop. It's a line. At the boundary between the minor loop and the major line, there is a gate that transfers bubbles between the two loops. In recent years, with the increase in the density of magnetic bubble elements, a folded minor loop as shown in FIG. 1 has come to be used in order to ensure the spatial margin of the gate.

In such a minor loop, there is a portion where the outer corner 4 and the linear transfer path 3 face each other, and FIG. 2 shows in detail the portion where the two face each other. As shown in the figure, a generally circular button having the same shape as the 1-bit element of the linear transfer path is usually used at the outer corner. In that case, a malfunction is likely to occur in which the bubble that has traveled around the outer course jumps to the cusp of the opposing straight transfer path. For this reason, the third
As shown in the figure, the bias margin when the bubble transfers around the outer corner is narrower than that of the straight transfer path. In practical devices, it is necessary to have a sufficient bias margin with a rotating magnetic field of about 500 e, but the width of the bias margin at this outer corner is 273, which is 7%, of that of the straight transfer path.
There is no other choice.

[Purpose of the invention]

An object of the present invention is to provide a magnetic bubble element with a sufficiently wide bubble transfer margin at the outer corner.

[Summary of the invention]

FIG. 4 shows the relationship between the distance Q between the outer corner and the straight transfer path shown in FIG. 2 and the bubble transfer margin. In a transfer path with a cell size of 4 μm×4 μm, 2 is typically 4 μm. In this case, the bias magnetic field margin is only 7% at a rotating magnetic field H,=5000, as described above.

However, as Q increases, the margin width widens, and = 8μ
In m, the margin width is 13%. This is because the distance between the tip A of the outer corner and the cusp B of the straight transfer path has increased, making it difficult for bubbles to jump from A to B.

As is clear from the above results, by increasing the distance between the tip of the outer corner and the cusp of the opposing linear transfer path, the lower limit of the bias magnetic field margin can be lowered (improved) and a wider margin can be obtained. can.

The present invention improves bubble transfer by increasing the distance between the tip of the outer corner and the cusp in question by making the bit length of the element facing the outer corner longer than the bit length of other elements in the straight transfer path. It is something that acquires characteristics.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. This figure shows the shape of a button near the outer corner of an ion implantation transfer path with a cell size of 4 μm×4 μm. The length L of the element 7 facing the outer corner 4 in the straight transfer path is longer than the length of the other elements (4 μm). FIG. 6 shows the bias magnetic field margin for bubble transfer at the outer corner when such a batten shape is used. As L increases from 4 μm, the lower limit of the margin decreases and the margin width increases. When L was 6 μm, the margin matched that of a straight transfer path, and a margin width of 13% was obtained.

FIG. 7 shows an example in which a snake-shaped ion implantation transfer path is used, and the cell size is 4 μm x 3 and 5 μm.

Also here, the length L of the element 7 on the straight transfer path facing the outer corner 4 was made longer than the length of the other elements (4 μm).

The gap between the straight transfer paths.

Since this is the same as the example shown in FIG. 6, the relationship between L and the bias magnetic field margin is almost the same as that shown in FIG. 6, and L
= 6 μm, the bias magnetic field margin was 13%.

〔Effect of the invention〕

According to the present invention, the bias magnetic field margin for bubble transfer at the outer corner of an ion implantation type magnetic bubble element is set to 1.
3%, and stable operation can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic bubble element, FIG. 2 is a plan view of the vicinity of a conventional outer corner, and FIGS. 3 and 4. FIG. 6 is a graph showing the bubble transfer margin, and FIGS. 5 and 7 are plan views of the vicinity of the outer corner of a bubble element according to an embodiment of the present invention.

Claims (1)

[Claims] A magnetic bubble element has a magnetic bubble transfer path formed by selectively implanting ions into a magnetic material capable of holding magnetic bubbles, and a portion where an outer corner that changes the direction of magnetic bubble transfer by 180° and a straight transfer path are opposed to each other. In an element having
A magnetic bubble element characterized in that the bit length of an element facing an outer corner in a straight transfer path is longer than the bit length of other elements.